1. Field of the Invention
The present invention relates to a plasma display device and a driving method thereof.
2. Discussion of the Background
A plasma display device is a flat panel display that uses plasma generated by a gas discharge process to display characters or images. It includes, depending on its size, more than several scores to millions of pixels arranged in a matrix pattern.
According to a typical plasma display device, each frame is divided into a plurality of subfields, and each subfield has a reset period, an address period, and a sustain period.
In the reset period, wall charges formed by a previous sustain discharge are erased, and new wall charges are set up so that the next addressing can be stably performed.
In the address period, a scan pulse is applied to a scan electrode and an address voltage is applied to an address electrode such that turn-on cells (i.e., cells to be turned on) are selected and wall charges accumulate to the turn-on cells (i.e., addressed cells).
In the sustain period, a sustain voltage causes the addressed cells to discharge, thus displaying an image.
According to a conventional driving method, the addressing is sequentially performed on all the scan electrodes in the address period to create an internal wall voltage. However, the internal wall voltages of the scan electrodes that are selected in the earlier stages may be reduced, which results in reduced margins.
In addition, a reset discharge is weak and thus light generated from the reset discharge is ignored. Therefore, a subfield with a weight value of 1 for expressing a gray scale 1 is represented by address light generated from an address discharge and sustain light generated from a sustain discharge. However, a brightness level of the minimum unit of light (minimum sustain light) generated from the sustain discharge is excessively high to express a low gray scale according to the conventional driving method. The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention, and therefore, unless explicitly described to the contrary, it should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known in this country to a person of ordinary skill in the art.